Microscope objective lens system

ABSTRACT

A microscope objective lens system which comprises a front and a rear lens group, the former comprising a first positive meniscus lens component, a second positive lens component, a third positive cemented lens component and a fourth positive cemented lens component, and the latter comprising a fifth cemented lens component, the system enabling to achieve the flattening of an image plane widely towards the surrounding area of visual field.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a microscope objective lens system andmore particularly to an achromatic microscope objective lens systemhaving a flat field.

(b) Description of the Prior Art

In a conventional microscope objective lens system of this type,although an image plane was flat, it was not sufficiently flat to thesurrounding area of the visual field and only in the vicinity of thecentral portion was there a flat image plane. Further, when the imageplane was flat over a comparatively large area, the numerical aperturewas small.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide amicroscope objective lens system which achieves the flattening of animage plane extended further towards the surrounding area of the visualfield as compared with conventional systems and wherein the numericalaperture is as large as N.A=0.7 with an excellent resolving power andwith magnification in the order of 40 times.

The objective lens system according to the present invention comprises afront lens group comprising a first lens component of a positivemeniscus lens having its concave surface faced to the object side, asecond lens component of a positive lens, a third lens component of apositive cemented lens, and a fourth lens component of a positivecemented lens, and a rear lens group comprising a fifth lens componentof a cemented lens having its concave surface faced to the image side,these lens components being arranged one after another from the objectside. This lens system satisfies each of the conditions enumeratedbelow:

(1) -0.05≦f₁ /f₂ ≦0.05

(2) 1.3≦r₂ /r₁ ≦1.75

(3) 70≦[(ν₄ -ν₃)+(ν₆ -ν₅)]≦90

(4) θ₇ -θ₈)/(ν₈ -ν₇)≦0.005

wherein the reference symbols f₁ and f₂ represent equivalent focallengths of the front lens group and the rear lens group, respectively,r₁ and r₂ represent radii of curvature of the surface on the object sideand the surface on the image side of the first lens component,respectively, ν₃, ν₄, ν₅, ν₆, ν₇ and ν₈ represent Abbe's numbers of boththe lenses of the third lens component, both the lenses of the fourthlens component and both the lenses of the fifth lens component,respectively, and θ₇ and θ₈ represent θ defined by θ=(n_(g)-n_(F))/(n_(F) -n_(c)) of both the lenses of the fifth lens component,respectively.

In the objective lens system according to the present invention, thepower of the rear lens group is made low and, therefore, the condition(1) is established in order to adjust the curvature of field and comaticaberration. In the condition (1), when f₁ /f₂ exceeds the upper limit,that is, the power of the rear lens group becomes high at the positivevalue, the curvature of field is overcorrected and the asymmetricalcharacter of coma is markedly aggravated. Moreover, there arises a greatdifficulty in correcting spherical aberration. Further, when f₁ /f₂exceeds the lower limit of the condition (1), that is, the power of therear lens group becomes strong at the negative value, the curvature offield is aggravated and chromatic aberration increases to thatcorrection of the chromatic aberration and of the spherical aberrationbecomes difficult.

Next, the condition (2) is for determining a refracting power of theconcave meniscus lens of the first lens component. This condition isnecessary in order to correct the Petzval's sum, to eliminate thecurvature of field and thereby to correct the spherical aberration andthe comatic aberration of the entire system. Above the upper limit ofthe condition (2), curvature of field is overcorrected and comaticaberration caused by spherical aberration of oblique ray flux isundercorrected. On the contrary, below the lower limit, curvature offield becomes overcorrected.

The condition (3) is for determining the total dispersion differences inthe achromatic lenses of the front lens group and this maintains thebalance between longitudinal chromatic aberration and lateral chromaticaberration of the entire system. Above the upper limit of the condition(3), when lateral chromatic aberration is sufficiently corrected,marginal rays of longitudinal chromatic aberration of short-wavelengthrays are overcorrected and, therefore, these come out on the image asflares thereby aggravating contrast in the image. Below the lower limitof the condition (3), when longitudinal chromatic aberration issufficiently corrected, the amount of undercorrection of lateralchromatic aberration becomes too great.

The condition (4) is for decreasing a secondary spectrum of chromaticaberration which markedly hinders the central resolution. That is, byusing as the convex lens a glass having a high partial dispersion rateand using as the concave lens a glass having a small partial dispersionrate for the fifth lens component, the secondary spectrum of chromaticaberration is made low so that an adverse effect on the image isavoided. Outside of the condition (4), it is not possible to decreasethe secondary spectrum.

Further, the objective lens of the present invention may be improved byapplying the following respective conditions in addition to theconditions explained herein above.

(5) 1.4≦|r₁₀ /r ₁₁ |≦2.5

(6) 1.3≦|r₁₁ /r₁₃ |≦1.8

(7) -0.2≦(n₂ -1)/(r₃)·f≦0.03

(8) -0.1≦(n₅ -1)/r₈ ·f≦0.1

(9) 0.35f<(d₁)/(n₁)+d₂ <f

wherein the reference symbol f represents a focal length of the entiresystem, r₃, r₈, r₁₀, r₁₁ and r₁₃ represent radii of curvature of thesurface on the object side of the second lens component, the surface onthe object side and the surface on the image side of the fourth lenscomponent and the surface on the object side and the surface on theimage side of the fifth lens component, respectively, d₁ represents athickness of the first lens component, d₂ represents an airspace betweenthe first lens component and the second lens component, and n₁, n₂, andn₅ represent refractive indices of the first lens component, the secondlens component and the lens on the object side of the fourth lenscomponent, respectively.

Among the above mentioned conditions, the conditions (5) and (6) arenecessary for correction the Petzval's sum and for eliminating curvatureof field and astigmatic difference and, when |r₁₀ /r₁₁ | and |r₁₁ /r₁₃ |exceed the upper limits of these respective conditions, the curvature offield is overcorrected and the zonal spherical aberration caused byspherical aberration of oblique ray flux is increased. Below the lowerlimits, curvature of field and astigmatic difference are undercorrected.Further, the conditions (7) and (8) are to adjust astigmatic differenceand to eliminate asymmetrical coma and, when (n₂ -1)/r₃ ·f and (n₅-1)/r₈ ·f exceed the upper limits of the respective conditions,astigmatic difference is undercorrected and asymmetrical coma caused byinward coma is increased. Below the lower limits, astigmatic differenceis overcorrected and asymmetrical coma caused by outward coma isincreased. The condition (9) together with the conditions (1), (2), (5),(6), (7) and (8) is effective for further improving the curvature offield and comatic aberration. Above the upper limit of this condition(9), the curvature of field is undercorrected and comatic aberrationcaused by oblique ray flux is overcorrected. Below the lower limit ofthis condition, curvature of field is overcorrected and comaticaberration is undercorrected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a sectional view illustrating the composition of themicroscope objective lens system according to the present invention;

FIG. 2 illustrates curves showing the aberration characteristics of theEmbodiment 1;

FIG. 3 illustrates curves showing the aberration characteristics of theEmbodiment 2;

FIG. 4 illustrates curves showing the aberration characteristics of theEmbodiment 3;

FIG. 5 illustrates curves showing the aberration characteristics of theEmbodiment 4;

FIG. 6 illustrates curves showing the aberration characteristics of theEmbodiment 5;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, some preferred embodiments of the present invention relating to themicroscope objective lens system as described above are given below:

    ______________________________________                                        Embodiment 1                                                                  ______________________________________                                        f = 1.0  β = 40X,                                                                            N.A = 0.7,   W.D = 0.1657                                 ______________________________________                                        r.sub.1 = -0.6362                                                                       d.sub.1 = 1.0847                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -1.0336                                                                       d.sub.2 = 0.0246                                                    r.sub.3 = -15.5604                                                                      d.sub.3 = 0.7229                                                                         n.sub.2 = 1.497                                                                           ν.sub.2 81.60                             r.sub.4 = -1.7302                                                                       d.sub.4 = 0.0246                                                    r.sub.5 = -8.6105                                                                       d.sub.5 = 0.2997                                                                         n.sub.3 = 1.5213                                                                          ν.sub.3 = 52.55                           r.sub.6 = 1.8391                                                                        d.sub.6 = 0.9229                                                                         n.sub.4 = 1.497                                                                           ν.sub.4 = 81.60                           r.sub.7 = -2.6282                                                                       d.sub.7 = 0.0345                                                    r.sub.8 = 75.5106                                                                       d.sub.8 = 0.2462                                                                         n.sub.5 =  1.7847                                                                         ν.sub.5 = 26.22                           r.sub.9 = 2.3155                                                                        d.sub.9 = 0.6402                                                                         n.sub.6 = 1.497                                                                           ν.sub.6 = 81.60                           r.sub.10 = -3.7586                                                                      d.sub.10 = 3.9990                                                   r.sub.11 = 2.0982                                                                       d.sub.11 = 1.0746                                                                        n.sub.7 = 1.783                                                                           ν.sub.7 = 36.15                           r.sub.12 = 3.3781                                                                       d.sub.12 = 0.4765                                                                        n.sub.8 = 1.6134                                                                          ν.sub.8 = 43.84                           r.sub.13 = 1.2170                                                                       f.sub.1 = 1.504                                                                          f.sub.2 = -150.418                                                 O.sub.7 = 0.5870                                                                         O.sub.8 = 0.5623                                         ______________________________________                                    

    ______________________________________                                        Embodiment 2                                                                  ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1654                                 ______________________________________                                        r.sub.1 = -0.6378                                                                       d.sub.1 = 1.1615                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -1.0741                                                                       d.sub.2 = 0.0246                                                    r.sub.3 = -22.5264                                                                      d.sub.3 = 0.7707                                                                         n.sub.2 = 1.497                                                                           ν.sub.2 = 81.60                           r.sub.4 = -1.8590                                                                       d.sub.4 = 0.0246                                                    r.sub.5 = -80.9474                                                                      d.sub.5 = 0.3532                                                                         n.sub.3 = 1.52682                                                                         ν.sub.3 = 51.12                           r.sub.6 = 1.8277                                                                        d.sub.6 = 0.9712                                                                         n.sub.4 = 1.497                                                                           ν.sub.4 = 81.60                           r.sub.7 = -2.9691                                                                       d.sub.7 = 0.0344                                                    r.sub.8 = 61.0911                                                                       d.sub.8 = 0.2458                                                                         n.sub.5 =  1.80518                                                                        ν.sub.5 = 25.43                           r.sub.9 = 2.2709                                                                        d.sub.9 = 0.6391                                                                         n.sub.6 = 1.497                                                                           ν.sub.6 = 81.60                           r.sub.10 = -4.0145                                                                      d.sub.10 = 4.0669                                                   r.sub.11 = 1.9044                                                                       d.sub.11 = 0.9361                                                                        n.sub.7 = 1.74077                                                                         ν.sub.7 = 27.79                           r.sub.12 = 2.1142                                                                       d.sub.12 = 0.3427                                                                        n.sub.8 = 1.6134                                                                          ν.sub.8 = 43.84                           r.sub.13 = 1.2113                                                                       f.sub.1 = 1.475                                                                          f.sub.2 = -44.593                                        O.sub.7 = 0.6060                                                                        O.sub.8 = 0.5623                                                    ______________________________________                                    

    ______________________________________                                        Embodiment 3                                                                  ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1638                                 ______________________________________                                        r.sub.1 = -0.5898                                                                       d.sub.1 = 1.0492                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -1.0096                                                                       d.sub.2 = 0.0243                                                    r.sub.3 = -14.0057                                                                      d.sub.3 = 0.6459                                                                         n.sub.2 = 1.4925                                                                          ν.sub.2 = 81.90                           r.sub.4 = -1.6253                                                                       d.sub.4 = 0.0243                                                    r.sub.5 = -38.5954                                                                      d.sub.5 = 0.2779                                                                         n.sub.3 = 1.5213                                                                          ν.sub.3 = 52.55                           r.sub.6 = 1.7252                                                                        d.sub.6 = 0.8951                                                                         n.sub.4 = 1.4925                                                                          ν.sub.4 = 81.90                           r.sub.7 = -2.6818                                                                       d.sub.7 = 0.0341                                                    r.sub.8 = -276.8809                                                                     d.sub.8 = 0.2434                                                                         n.sub. 5 = 1.80518                                                                        ν.sub.5 = 25.43                           r.sub.9 = 2.2340                                                                        d.sub.9 = 0.6328                                                                         n.sub.6 = 1.4925                                                                          ν.sub.6 = 81.90                           r.sub.10 = -3.4057                                                                      d.sub.10 = 3.9883                                                   r.sub.11 = 1.9127                                                                       d.sub.11 = 0.9450                                                                        n.sub.7 = 1.72342                                                                         ν.sub.7 = 37.95                           r.sub.12 = 6.4511                                                                       d.sub.12 = 0.3432                                                                        n.sub.8 = 1.61484                                                                         ν.sub.8 = 51.17                           r.sub.13 = 1.1849                                                                       f.sub.1 = 1.421                                                                          f.sub.2 = -161.569                                                 O.sub.7 = 0.5835                                                                         O.sub.8 = 0.5573                                         ______________________________________                                    

    ______________________________________                                        Embodiment 4                                                                  ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1638                                 ______________________________________                                        r.sub.1 = -0.5775                                                                       d.sub.1 = 1.0304                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -0.9776                                                                       d.sub.2 = 0.0243                                                    r.sub.3 = -127.6624                                                                     d.sub.3 = 0.6167                                                                         n.sub.2 = 1.4925                                                                          ν.sub.2 = 81.90                           r.sub.4 = -1.6702                                                                       d.sub.4 = 0.0243                                                    r.sub.5 = -13.3607                                                                      d.sub.5 = 0.2872                                                                         n.sub.3 = 1.5213                                                                          ν.sub.3 = 52.55                           r.sub.6 = 1.6493                                                                        d.sub.6 = 0.9031                                                                         n.sub.4 = 1.4925                                                                          ν.sub.4 = 81.90                           r.sub.7 = -2.6376                                                                       d.sub.7 = 0.0341                                                    r.sub.8 = -149.0899                                                                     d.sub.8 = 0.2434                                                                         n.sub.5 =  1.80518                                                                        ν.sub.5 = 25.43                           r.sub.9 = 2.1982                                                                        d.sub.9 = 0.6328                                                                         n.sub.6 = 1.4925                                                                          ν.sub.6 = 81.90                           r.sub.10 = -3.2426                                                                      d.sub.10 = 3.9939                                                   r.sub.11 = 1.9263                                                                       d.sub.11 = 0.9516                                                                        n.sub.7 = 1.7495                                                                          ν.sub.7 = 35.27                           r.sub.12 = 5.6938                                                                       d.sub.12 = 0.3517                                                                        n.sub.8 = 1.6134                                                                          ν.sub.8 = 43.84                           r.sub.13 = 1.1734                                                                       f.sub.1 = 1.412                                                                          f.sub.2 = 3360.713                                                 O.sub.7 = 0.5885                                                                         O.sub.8 = 0.5623                                         ______________________________________                                    

    ______________________________________                                        Embodiment 5                                                                  ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1629                                 ______________________________________                                        r.sub.1 = -0.5879                                                                       d.sub.1 = 1.1268                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -0.9712                                                                       d.sub.2 = 0.0242                                                    r.sub.3 = -3.4741                                                                       d.sub.3 = 0.5324                                                                         n.sub.2 = 1.497                                                                           ν.sub.2 = 81.60                           r.sub.4 = -1.7216                                                                       d.sub.4 = 0.0242                                                    r.sub.5 = 3.4827                                                                        d.sub.5 = 0.3555                                                                         n.sub.3 = 1.5213                                                                          ν.sub.3 = 52.55                           r.sub.6 = 1.4761                                                                        d.sub.6 = 0.9526                                                                         n.sub.4 = 1.497                                                                           ν.sub.4 = 81.60                           r.sub.7 = -2.7742                                                                       d.sub.7 = 0.0339                                                    r.sub.8 = -15.9252                                                                      d.sub.8 = 0.2420                                                                         n.sub.5 =  1.7847                                                                         ν.sub.5 = 26.22                           r.sub.9 = 1.6468                                                                        d.sub.9 = 0.6292                                                                         n.sub.6 = 1.497                                                                           ν.sub.6 = 81.60                           r.sub.10 = -4.3063                                                                      d.sub.10 = 4.0024                                                   r.sub.11 = 1.9340                                                                       d.sub.11 = 0.9124                                                                        n.sub.7 = 1.7495                                                                          ν.sub.7 = 35.27                           r.sub.12 = -80.2098                                                                     d.sub.12 = 0.2986                                                                        n.sub.8 = 1.6134                                                                          ν.sub.8 = 43.84                           r.sub.13 = 1.1830                                                                       f.sub.1 = 1.332                                                                          f.sub.2 = 79.840                                                   O.sub.7 = 0.5885                                                                         O.sub.8 = 0.5623                                         ______________________________________                                    

wherein the reference symbols f represents a focal length, β representsa lateral magnification, N.A. represents a numerical aperture, W.D.represents a working distance, r₁ through r₁₃ represent radii ofcurvature of the respective surfaces of the lens, d₁ representsthickness of the respective lenses and air spaces therebetween, n₁through n₈ represent refractive indices of the respective lenses and ν₁through ν₈ represent Abbe's numbers of the respective lenses.

I claim:
 1. A microscope objective lens system comprising a front lensgroup comprising a first lens component of a positive meniscus lenshaving its concave surface faced to the object side, a second lenscomponent of a positive lens, a third lens component of a positivecemented lens, and a fourth lens component of a positive cemented lens,and a rear lens group comprising a fifth lens component of a cementedlens having its concave surface faced to the image side, and said lenssystem satisfying the following conditions:(1) -0.05≦f₁ /f₂ ≦0.05 (2)1.3≦r₂ /r₁ ≦1.75 (3) 70≦[(ν₄ -ν₃)+(ν₆ -ν₅)]≦90 (4) (θ₇ -θ₈)/(ν₈-ν₇)≦0.005 (5) 1.68<|r₁₀ /r₁₁ |≦2.5 (6) 1.57≦|r₁₁ /r₁₃ |≦1.8 (7)-0.2≦(n₂ -1)/(r₃)·f≦0.03 (8) -0.1≦(n₅ -1)/(r₈)·f≦0.1 (9) 0.6f<(d₁/n₁)+d₂ <fwherein the reference symbols f₁ and f₂ represent equivalentfocal lengths of the front lens group and the rear lens group,respectively, r₁ and r₂ represent radii of curvature of the surface onthe object side and the surface on the image side of the first lenscomponent, respectively, ν₃, ν₄, ν₅, ν₆, ν₇ and ν₈ represent Abbe'snumbers of both the lenses of the third lens component, both the lensesof the fourth lens component and both the lenses of the fifth lenscomponent, respectively, θ₇ and θ₈ represent θ defined by θ=(n_(g)-n_(F))/(n_(F) -n_(c)) of both the lenses of the fifth lens component,respectively, the reference symbol f represents a focal length of theentire system, r₃, r₈, r₁₀, r₁₁ and r₁₃ represent radii of curvature ofthe surface on the object side of the second lens component, the surfaceon the object side and the surface on the image side of the fourth lenscomponent and the surface on the object side and the surface on theimage side of the fifth lens component, respectively, d₁ represents athickness of the first lens component, d₂ represents an airspace betweenthe first lens component and the second lens component, and n₁, n₂ andn₅ represent refractive indices of the first lens component, the secondlens component and the lens on the object side of the fourth lenscomponent, respectively.
 2. A microscope objective lens system accordingto claim 2 having the following numerical data:

    ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1657                                 ______________________________________                                        r.sub.1 = -0.6362                                                                       d.sub.1 = 1.0847                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -1.0336                                                                       d.sub.2 = 0.0246                                                    r.sub.3 = -15.5604                                                                      d.sub.3 = 0.7229                                                                         n.sub.2 = 1.497                                                                           ν.sub.2 = 81.60                           r.sub.4 = -1.7302                                                                       d.sub.4 = 0.0246                                                    r.sub.5 = -8.6105                                                                       d.sub.5 = 0.2997                                                                         n.sub.3 = 1.5213                                                                          ν.sub.3 = 52.55                           r.sub.6 = 1.8391                                                                        d.sub.6 = 0.9229                                                                         n.sub.4 = 1.497                                                                           ν.sub.4 = 81.60                           r.sub.7 = -2.6282                                                                       d.sub.7 = 0.0345                                                    r.sub.8 = 75.5106                                                                       d.sub.8 = 0.2462                                                                         n.sub.5 = 1.7847                                                                          ν.sub.5 = 26.22                           r.sub.9 = 2.3155                                                                        d.sub.9 = 0.6402                                                                         n.sub.6 = 1.497                                                                           ν.sub.6 = 81.60                           r.sub.10 = -3.7586                                                                      d.sub.10 = 3.9990                                                   r.sub.11 = 2.0982                                                                       d.sub.11 = 1.0746                                                                        n.sub.7 = 1.783                                                                           ν.sub.7 = 36.15                           r.sub.12 = 3.3781                                                                       d.sub.12 = 0.4765                                                                        n.sub.8 = 1.6134                                                                          ν.sub.8 = 43.84                           r.sub.13 = 1.2170                                                                       f.sub.1 = 1.504                                                                          f.sub.2 = -150.418                                                 O.sub.7 = 0.5870                                                                         O.sub.8 = 0.5623                                         ______________________________________                                    

wherein the reference symbol f represents a focal length of the entiresystem, r₁ through r₁₃ represent radii of curvature of the respectivesurfaces of the lens component, d₁ through d₁₂ represent thicknesses ofthe respective lens elements and the airspaces therebetween, n₁ throughn₈ represent refractive indices of the respective lens elements and ν₁through ν₈ represent Abbe's numbers of the respective lens elements. 3.A microscope objective lens system according to claim 1 having thefollowing numerical data:

    ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1654                                 ______________________________________                                        r.sub.1 = -0.6378                                                                       d.sub.1 = 1.1615                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -1.0741                                                                       d.sub.2 = 0.0246                                                    r.sub.3 = -22.5264                                                                      d.sub.3 = 0.7707                                                                         n.sub.2 = 1.497                                                                           ν.sub.2 = 81.60                           r.sub.4 = -1.8590                                                                       d.sub.4 = 0.0246                                                    r.sub.5 = -80.9474                                                                      d.sub.5 = 0.3532                                                                         n.sub.3 = 1.52682                                                                         ν.sub.3 = 51.12                           r.sub.6 = 1.8277                                                                        d.sub.6 = 0.9712                                                                         n.sub.4 = 1.497                                                                           ν.sub.4 = 81.60                           r.sub.7 = -2.9691                                                                       d.sub.7 = 0.0344                                                    r.sub.8 = 61.0911                                                                       d.sub.8 = 0.2458                                                                         n.sub.5 = 1.80518                                                                         ν.sub.5 = 25.43                           r.sub.9 = 2.2709                                                                        d.sub.9 = 0.6391                                                                         n.sub.6 = 1.497                                                                           ν.sub.6 = 81.60                           r.sub.10 = -4.0145                                                                      d.sub.10 = 4.0669                                                   r.sub.11 = 1.9044                                                                       d.sub.11 = 0.9361                                                                        n.sub.7 = 1.74077                                                                         ν.sub.7 = 27.79                           r.sub.12 = 2.1142                                                                       d.sub.12 = 0.3427                                                                        n.sub.8 = 1.6134                                                                          ν.sub.8 = 43.84                           r.sub.13 = 1.2113                                                                       f.sub.1 = 1.475                                                                          f.sub.2 = -44.593                                                  O.sub.7 = 0.6060                                                                         O.sub.8 = 0.5623                                         ______________________________________                                    

wherein the reference symbol f represents a focal length of the entiresystem, r₁ through r₁₃ represent radii of curvature of the respectivesurfaces of the lens component, d₁ through d₁₂ represent thicknesses ofthe respective lens elements and the airspaces therebetween, n₁ throughn₈ represent refractive indices of the respective lens elements and ν₁through ν₈ represent Abbe's numbers of the respective lens elements. 4.A microscope objective lens system according to claim 1 having thefollowing numerical data:

    ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1638                                 ______________________________________                                        r.sub.1 = -0.5898                                                                       d.sub.1 = 1.0492                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -1.0096                                                                       d.sub.2 = 0.0243                                                    r.sub.3 = -14.0057                                                                      d.sub.3 = 0.6459                                                                         n.sub.2 = 1.4925                                                                          ν.sub.2 = 81.90                           r.sub.4 = -1.6253                                                                       d.sub.4 = 0.0243                                                    r.sub.5 = -38.5954                                                                      d.sub.5 = 0.2779                                                                         n.sub.3 = 1.5213                                                                          ν.sub.3 = 52.55                           r.sub.6 = 1.7252                                                                        d.sub.6 = 0.8951                                                                         n.sub.4 = 1.4925                                                                          ν.sub.4 = 81.90                           r.sub.7 = -2.6818                                                                       d.sub.7 = 0.0341                                                    r.sub.8 = -276.8809                                                                     d.sub.8 = 0.2434                                                                         n.sub.5 = 1.80518                                                                         ν .sub.5 = 25.43                          r.sub.9 = 2.2340                                                                        d.sub.9 = 0.6328                                                                         n.sub.6 = 1.4925                                                                          ν.sub.6 = 81.90                           r.sub.10 = -3.4057                                                                      d.sub.10 = 3.9883                                                   r.sub.11 = 1.9127                                                                       d.sub.11 = 0.9450                                                                        n.sub.7 = 1.72342                                                                         ν.sub.7 = 37.95                           r.sub.12 = 6.4511                                                                       d.sub.12 = 0.3432                                                                        n.sub.8 = 1.61484                                                                         ν.sub.8 = 51.17                           r.sub.13 = 1.1849                                                                       f.sub.1 = 1.421                                                                          f.sub.2 = -161.569                                                 O.sub.7 = 0.5835                                                                         O.sub.8 = 0.5573                                         ______________________________________                                    

wherein the reference symbol f represents a focal length of the entiresystem, r₁ through r₁₃ represent radii of curvature of the respectivesurfaces of the lens component, d₁ through d₁₂ represent thicknesses ofthe respective lens elements and the airspaces therebetween, n₁ throughn₈ represent refractive indices of the respective lens elements and ν₁through ν₈ represent Abbe's numbers of the respective lens elements. 5.A microscope objective lens system according to claim 1 having thefollowing numerical data:

    ______________________________________                                        f = 1.0, β = 40X,                                                                            N.A = 0.7,   W.D = 0.1638                                 ______________________________________                                        r.sub.1 = -0.5775                                                                       d.sub.1 = 1.0304                                                                         n.sub.1 = 1.78472                                                                         ν.sub.1 = 25.71                           r.sub.2 = -0.9776                                                                       d.sub.2 = 0.0243                                                    r.sub.3 = -127.6624                                                                     d.sub.3 = 0.6167                                                                         n.sub.2 = 1.4925                                                                          ν.sub.2 = 81.90                           r.sub.4 = -1.6702                                                                       d.sub.4 = 0.0243                                                    r.sub.5 = -13.3607                                                                      d.sub.5 = 0.2872                                                                         n.sub.3 = 1.5213                                                                          ν.sub.3 = 52.55                           r.sub.6 = 1.6493                                                                        d.sub.6 = 0.9031                                                                         n.sub.4 = 1.4925                                                                          ν.sub.4 = 81.90                           r.sub.7 = -2.6376                                                                       d.sub.7 = 0.0341                                                    r.sub.8 = -149.0899                                                                     d.sub.8 = 0.2434                                                                         n.sub.5 = 1.80518                                                                         ν.sub. 5 = 25.43                          r.sub.9 = 2.1982                                                                        d.sub.9 = 0.6328                                                                         n.sub.6 = 1.4925                                                                          ν.sub.6 = 81.90                           r.sub.10 = -3.2426                                                                      d.sub.10 = 3.9939                                                   r.sub.11 = 1.9263                                                                       d.sub.11 = 0.9516                                                                        n.sub.7 = 1.7495                                                                          ν.sub.7 = 35.27                           r.sub.12 = 5.6938                                                                       d.sub.12 = 0.3517                                                                        n.sub.8 = 1.6134                                                                          ν.sub.8 = 43.84                           r.sub.13 = 1.1734                                                                       f.sub.1 = 1.412                                                                          f.sub.2 = -3360.713                                                O.sub.7 = 0.5885                                                                         O.sub.8 = 0.5623                                         ______________________________________                                    

wherein the reference symbol f represents a focal length of the entiresystem, r₁ through r₁₃ represent radii of curvature of the respectivesurfaces of the lens component, d₁ through d₁₂ represent thicknesses ofthe respective lens elements and the airspaces therebetween, n₁ throughn₈ represent refractive indices of the respective lens elements and ν₁through ν₈ represent Abbe's numbers of the respective lens elements. 6.A microscope objective lens system according to claim 1 having thefollowing numerical data:

    ______________________________________                                        f= 1.0,  β = 40X,                                                                            N.A = 0.7,   W.D = 0.1629                                 ______________________________________                                        r.sub.1 = -0.5879                                                                         d.sub.1 = 1.1268                                                                         n.sub.1 = 1.78472                                                                        ν.sub.1 = 25.71                          r.sub.2 = -0.9712                                                                         d.sub.2 = 0.0242                                                  r.sub.3 = -3.4741                                                                         d.sub.3 = 0.5324                                                                         n.sub.2 = 1.497                                                                          ν.sub.2 = 81.60                          r.sub.4 = -1.7216                                                                         d.sub.4 = 0.0242                                                  r.sub.5 = 3.4827                                                                          d.sub.5 = 0.3555                                                                         n.sub.3 = 1.5213                                                                         ν.sub.3 = 52.55                          r.sub.6 = 1.4761                                                                          d.sub.6 = 0.9526                                                                         n.sub.4 = 1.497                                                                          ν.sub.4 = 81.60                          r.sub.7 = -2.7742                                                                         d.sub.7 = 0.0339                                                  r.sub.8 = -15.9252                                                                        d.sub.8 = 0.2420                                                                         n.sub.5 = 1.7847                                                                         ν.sub. 5 = 26.22                         r.sub.9 = 1.6468                                                                          d.sub.9 = 0.6292                                                                         n.sub.6 = 1.497                                                                          ν.sub.6 = 81.60                          r.sub.10 = -4.3063                                                                        d.sub.10 = 4.0024                                                 r.sub.11 = 1.9340                                                                         d.sub.11 = 0.9124                                                                        n.sub.7 = 1.7495                                                                         ν.sub.7 = 35.27                          r.sub.12 = -80.2098                                                                       d.sub.12 = 0.2986                                                                        n.sub.8 = 1.6134                                                                         ν.sub.8 = 43.84                          r.sub.13 = 1.1830                                                                         f.sub.1 = 1.332                                                                          f.sub.2 = 79.840                                                   O.sub.7 = 0.5885                                                                         O.sub.8 = 0.5623                                       ______________________________________                                    

wherein the reference symbol f represents a focal length of the entiresystem, r₁ through r₁₃ represent radii of curvature of the respectivesurfaces of the lens component, d₁ through d₁₂ represent thicknesses ofthe respective lens elements and the airspaces therebetween, n₁ throughn₈ represent refractive indices of the respective lens elements and ν₁through ν₈ represent Abbe's numbers of the respective lens elements.